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Old Jan 18, 2005, 2:56 PM   #5
BillDrew
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Location: Hay River Township, WI
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slipe wrote:
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The fair way to make the comparison would be to take a picture at 8Mp and one at 5Mp. Take both to the size you want for output – but the same size in pixels for both images. Then compare noise.
That is another fair test.

slipe wrote:
Quote:
I think what Bill is saying is that if you view them both at 100% you will see more noise in the larger image. Another way of saying it is that you will see more noise in an image if you blow it up. I can't disagree with that. But downsizing an image doesn't really reduce the noise regardless of whether it is done in the camera or in an image editor after the picture is taken.
No, I am saying the noise is decreased by downsizing, assuming averaging of pixels instead of simply throwing them away. The width of the histogram (Standard Deviantion) of a uniformly colored subject in uniform light is a measure of noise. That does decrease with downsizing.
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